The European Jewish Congress (EJC) has responded with "horror" to today's deadly shooting at Belgium's Jewish Museum, condemning the "murderous attack at the Jewish museum in central Brussels today" and sending its "condolences to the families of the victims."

EJC President Dr. Moshe Cantor echoed sentiments made in the immediate aftermath of the attack, saying that while a motive has not yet been established, the alarming rates of anti-Semitism in Belgium make it highly likely that the attack was a hate crime.

"While we don’t not yet have full information regarding the background to this attack, we are acutely aware of the permanent threat to Jewish targets in Belgium and across the whole of Europe," he said.

Earlier, Belgian Jewish community figure Joel Rubinfeld said the killings were definitely "a terrorist act" after two men were seen driving up and double-parking outside the museum.

The gunman opened fire, allegedly shooting indiscriminately before getting away.

Rubinfeld, who heads the country's anti-Semitic League, said the act was the result of "a climate of hate."

"This is once again, much like the savage murders in Toulouse, a clear example of where hate and anti-Semitism leads," Cantor added, referring to the anti-Semitic shooting in France in 2012 in which three children and a rabbi were murdered by a Muslim extremist.

"European governments must send out a clear message of zero tolerance towards any manifestation of anti-Semitism."

A crisis centre has been opened by the Consistoire Central and the Coordinating Committee of Belgian Jewish Organisations (CCOJB) and community leaders are in direct and permanent contact with police, local authorities and emergency services.